This invention relates to distributed digital systems, and more particularly, to distributed digital systems having a plurality of nodes coupled to a network for communicating between nodes, wherein a once closed network is opened to permit a variety of nodes to be coupled to the network.
There currently exists systems having a plurality of nodes operatively connected to a bus or network in which the nodes are developed by a single manufacturer who enforces strict control over the design of the nodes and over the functions to be performed by the nodes. Further, a predetermined protocol is utilized by the network which results in a "closed" environment.
In order to allow a user the option of selecting equipment of other manufactures, having differing protocols, and thereby expanding the capabilities and functionality of these systems, it is desired to have an "open" systems environment which permits the user to connect (directly or indirectly) these equipments of other manufacturers having differing designs to the network of the system. By opening up the system to these equipments, the reliability of the system is now susceptible to any errors (bugs, viruses, . . . ) of the new equipment being added which is not under the control of the manufacturer of the system.
Thus, the present invention provides a method for controlling window displays in the open system window environment while maintaining the high reliability that the system had before opening up the environment i.e., guaranteeing that display of the system, as a minimum, is provided to an operator.